Johann Georg Flach (age 19) is recorded on the 1767 census of Warenburg in Household No. 129 along with his stepfather Balthasar Bös.
The 1767 census does not record from where Johann Georg Flach came.
- Mai, Brent Alan. 1798 Census of the German Colonies along the Volga: Economy, Population, and Agriculture (Lincoln, NE: American Historical Society of Germans from Russia, 1999): Wr070.
- Pleve, Igor. Einwanderung in das Wolgagebiet, 1764-1767 Band 4 (Göttingen: Göttinger Arbeitskreis, 2008): 341.